(2019 Archived) - ARGUMENT IV: The Cosmic Radiation on Mars vs. the Ultraviolet Radiation on Venus.

Having written this in 2019, and originally published in 2021.. when I was 15 and 17, there would be inaccuracies that I would correct here. Having removed it, I'm publishing  again, for sake of completion so that the efforts wouldn't have gone to vain: Most of this still stands true - though some phrasings could be improved, a lot.  

Space is dangerous – there are many omnipresent threats which lurk in the dark vacuum of space, which wouldn’t hesitate to annihilate life as we know it; cosmic radiation is one of them, and Ultraviolet (UV) radiation is a slightly less deadly but just-as irritating version of it. Fortunately, for us, the Earth’s magnetosphere, ozone layer, and thick atmosphere provides a haven for humanity and all of Earth-life, from cosmic radiation and most of UV. Yet, like all other circumstances which make the Earth so homely to life – we don’t often get to think-about or acknowledge it, let alone even know about it at all!

Imagine a geologically frozen world, which in turn, doesn’t have a magnetosphere of any sort. Imagine a world having neither an ozone layer nor a thick atmosphere. That’s exactly what Mars is! Mars might not be geologically ‘dead’, but it doesn’t have an oppositely-rotating molten inner and outer core, which is the prerequisite of a terrestrial world in order to have a magnetic field. How dramatically did the absence of a magnetosphere affect the red planet? In fact, what would happen if it were true on the Earth?

Let’s imagine a scenario where the Earth was to spontaneously loose her magnetosphere for unexplained reasons. Obviously, cosmic radiation is now capable of penetrating through the Earth’s atmosphere and bombarding the surface. This new exposure to ionizing radiation would render almost all life on the Earth, including us, to succumb to radiation poisoning and die. Furthermore, the solar winds would now be capable in ‘blowing-away the Earth’s atmosphere rendering our blue marble to become further inhospitable to life. Although this scenario is completely hypothetical, it could be a reality for any planet with a weak magnetosphere. We have a good example for it – Mars itself.

Eons ago, Mars was quite an Earth-like planet – specifically during the Noachian eon, which was ~4.5 to 3.5 billion years ago. The Noachian Mars had large ocean-like water bodies, running rivers and perhaps even primordial forms of unsophisticated life ^[19].

Considering that Mars is technically still in the goldilocks zone of the sun, it isn’t surprising that that the Noachian Mars was a warm temperate world with a healthy atmosphere, but a slightly weak magnetic field. Unfortunately for the Noachian Mars, weakening geologic activity (required for a magnetic field), along with several asteroid impacts lead to the Martian magnetosphere being slowly starved until it died-off. It allowed the solar winds to directly interact with the Martian ionosphere and blow away the Martian atmosphere over the eras, and reduced the Martian atmosphere to the mere pittance it is today ^[19]. This slow phenomenon still prevails on Mars, and it won’t be stopping any time soon.

The cosmos is like an oven – not just of microwaves, but of ionizing-radiation. Now, without a magnetosphere or a thick atmospheric cover, cosmic radiation is free to penetrate the Martian atmosphere – the vacuum to the first decimal place – and bombard the Martian surface with little-to-no resistance – almost as if there wasn’t an atmosphere at all!.An atmosphere and magnetosphere are sort-of like a planet’s protective clothing against the various radiations and threats of the cosmos. Simply, Mars’ near-vacuumish clothing is just too flimsy and feeble to protect against the ionizing radiations of our cosmic oven– Mars is naked. Mars is but a vulnerable naked rock in an ionizing-radiation oven

For more formal proof: The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover measured cosmic ray and energetic particle radiation environment on the Martian surface. It estimated a total mission dose of ~1.01 Sieverts of ionizing cosmic radiation, for a Mars surface mission in our current solar cycle ^[20]! That is way above the recommended radiation dose for a mission! Plus, it is also for our current solar cycle; solar cycles change regularly at 8-15 year time-periods with an average of 11 years ^[21], which with the threats of solar flares and coronal mass ejections could raise radiation exposure to higher levels. Just imagine how it is like to live under such radiation conditions for a whole life-time, as with the Martians of a permanent colony!

Exposure to radiation of that calibre could give the unprotected Martian-immigrants radiation sickness; which causes nausea, vomiting, anorexia and fatigue, and tissue degeneration; which in-turn would give rise to cataracts and cardio-circulatory degeneration. More acute effects include; increased risk of cancer and damage of central nervous system, which might manifest themselves as altered cognitive function, decreased motor function and behavioural change^{[22, 23]}. To make this less like homework, I would like to break it down – initial exposure might give rise to;

·        Radiation Sickness

·        Tissue Degeneration

·        Nausea

·        Cataracts

·        Vomiting

·        Cardio-circulatory Degeneration

·        Anorexia

·        Fatigue

Prolonged exposure might even prove to be deadly – potentially fatal with acute effects which might include^{[22, 23]};

·        Increased risk of cancer

·        Damaged Central Nervous System

·        Altered Cognitive Function

·        Decreased Motor Function

·        Behavioural Change

But surely, there are ways to avoid it, right? One such strategy would be taken is to take cover in natural shelter – the canyons and gorges like the Valles Marineris, Kasei Valles, Tiu Valles, and Ares Valles. There are also the impact basins like the Hellas Planitia and Argyre Planitia, and large craters like the Gale crater and the Huygens crater ^[15]. It’s a good strategy, but more precaution would be needed as water storage at the upper areas of the Martian bases and habitats, and most importantly being buried. Being buried metres underground is the most efficient way of doing so. But it comes at a cost – the sacrifice of windows, which could make the Martian bases feel more confined, isolated, claustrophobic and psychologically unsound; especially for life-long missions. I shall talk more about it in a future argument. But, the inevitable fact is that most of Martian life would be led indoors.

Still, imagine being consigned metres underground, to stay the majority of your years– Seldom having the chance to marvel at the spectacular red desert outside, without the discomfort of a pressurized suit and seldom seeing the faint Martian sunset which blue-ens the western sky, with the nostalgia of home. Also, the pressurized spacesuits used for EVA and outdoor activities would likely give unsatisfactory protection from the omnipresent comic radiation; which by-the-way, is inescapable and always present in every minute of the 24 hour and 39 minute sol (Martian day) ^[15].

Thus time given for EVA and outdoor activities on Mars must be meticulously timed, as I believe that most exposure to cosmic radiation occurs at that time. In a Martian lifetime, the accumulated exposure to cosmic radiation could lead to the aforementioned effects of radiation and possibly even infertility ^{[22, 23]}. Infertility is one of the few ways a civilization could meet its end, and if radiation-linked infertility were commonplace in the future Martian civilization, it could potentially lead to its downfall.

But, how does the Venusians compare? Venus too neither has a magnetosphere nor an ozone layer, meaning that cosmic radiation should be capable in penetrating the Venusian atmosphere to the level of the Venusian cloud-cities, right? No, no it doesn’t – it is because of there is still a thick atmosphere above the Venusian atmosphere to protect the cloud-cities and its inhabitants from being bombarded from the ionizing radiations of space ^[1]. It isn’t that it’s not a threat, as the flux of cosmic radiation can still penetrate far inside the Venusian atmosphere. But, “Even though the flux of ionizing radiation can be sterilizing, high in the atmosphere, the total dose delivered at the top of the habitable zone… is not likely to present a significant survival challenge”^[24].

That means that all of the aforementioned effects of exposure to cosmic radiation wouldn’t much of a concern for Venusian life – let alone, not even make a pennyworth of difference! The Venusians wouldn’t have to worry about timing with regard to exposure to cosmic radiation, and radiation-induced infertility would be a thing on Venus. The Venusian atmosphere is as much a haven from cosmic radiation as our own, and it itself is a gift to be cherished. The ionizing radiations of the cosmos would not haunt Venusian lifestyle as it does for Mars. I mean, the Venusian atmosphere is like thick protective clothing. To take a more anthropogenic perspective, imagine a lady over-dressed with dresses upon dresses, and protective clothing upon protective clothing – until literally immune to ionizing radiation. Venus would be blissful and heavenly for the Martians, but merely just worldly and home for the Venusians.

But, the Venusian atmosphere provides no protection from UV radiation, owing to the absence of an ozone layer. Even with an ozone layer, the UV we receive is adequate to give rise to painful sunburns, given the right conditions. How extreme of sunburn would a similar Venusian get? It’s not worth answering, as the sunburns wouldn’t be the greatest threat of UV; it is that without a magnetosphere or ozone layer, UV could be sterilizing, cause cancers and lead to a maladroit physiology as in cosmic radiation.

It should be noted that the Martian surface is also constantly bombarded by UV radiation, and the UV on Mars would typically cut the UV on Venus during selecting an advantage. Except that Venus lays 21AU closer to the sun and receives 42% more UV radiation than the Earth! That is, in essence, 218% more UV intake than Mars ^[1]! That sounds enormously large, but it can be avoided:

Sunscreen wouldn’t be quite practical, or helpful in protecting against the austere sunburns, that the Venusians might have to deal with. Instead we have a simpler option: “It is not hard to shield a habitat from UV or to protect from UV…outside a habitat. Specially coated glass for instance would do fine” ^[8]. Similar UV-protective coated glasses have been used in spectacles, as in mine, and it wouldn’t be much of a challenge to coat the interfaces to the outside, glass and related parts of the cloud-cities, with the UV-protective material. UV, and the sunburns and skin cancers it might give, would be an issue to the Venusians in such a circumstance.

With such a precautionary technique, the threat of UV would be obsolescent and technically non-existent on both Venus and Mars. Now we can focus on how to use the outdoor UV to our advantage. Since it is something common for both Venus and Mars, it wouldn’t need to be much described in this argument, with UV- based photo-disassociationary reactions with industrial value. But the point I want to make is that with 218% more UV available at the Venusian cloud-tops, such reactions would be much more efficient, and thus cost-effective.

Let’s do a quick recap on everything we’ve learnt so far, in this chapter: (1) Cosmic radiation is a problem on Mars, with several undesirable consequences. (2) Cosmic Radiation on Mars would lead to the Martians to live most of their lives metres underground, which can be psychologically agonizing. (3) EVA and outdoor activities on Mars would be limited to radiation hazards. (4) Cosmic Radiation is neither a threat nor a hazard to Venusian life. (5) UV is neither a hazard to Venus (nor Mars). (6) 218% more availability of UV on Venus than Mars, would make UV-based industry on Venus more profitable. This leads to the conclution that Venus and its cloud-cities are protected from cosmic radiation (and UV), and more suitable for human colonization.

[8] Walker, R. (2014, January 12). Will we build colonies that float over Venus like Buckminster Fuller’s “Cloud Nine?”  Retrieved from (https://www.science20.com/robert_inventor/will_we_build_colonies_that_float_over_venus_like_ buckminster_fullers_cloud_nine-127573).

[15] Wikipedia (at 2019, February). Retrieved from (https://en.m.wikipedia.org/wiki/Mars).

[19] Wikipedia (at 2019, February). Retrieved from (https://en.m.wikipedia.org/wiki/Noachian ).

[20] Hassler, D.M. & Zeitlin, C. &Wimmer-Schweingruber, R.F. &Ehresmann, B. &Rafkin, S. &Eigenbrode, J.L. &Brinza, D.E. &Weigle, G. &Böttcher, S. &Böhm, E. &Burmeister, S. &Guo, J. &Köhler, J. & Martin, C. & Reitz, G. &Cucinotta, F.A. & Myung-Hee, K. &Grinspoon, D. & Bullock, M.A. & Posner, A. & Gómez-Elvira, J. &Vasavada, A. &Grotzinger, J.P. & MSL Science Team. (2013, November 12). Mars’ Surface Radiation Environment Measured with the Mars Science Laboratory’s Curiosity Rover.

[21] Green, L. (2016). 15 million Degrees: a journey to the centre of the Sun. [Viking; Penguin Random House, UK]. Pp 221-225.

[22] Dunbar, B. (2018, June 11). The Human body in space. Retrieved from (https://www.nasa.gov/nrp/body_in_space).

[23] Wikram, L.A. (2006). Human Performance Considerations for Mars mission [Paper available online and for download at https://www.apu.edu/static/src/sites/research-

science/downloads/human performance mars mission.pdf].

[24] Dartnell, L.R. & Nordheim, T.A. & Patel, M.R. & Mason, J.P. & Coates, A.J. & Jones, G.H. (2015, September) Constraints on a potential aerial biosphere on Venus.I.Cosmic Rays. [Paper available online and for download at: http://researchgate.net/publication/278333688_constraints_ on_ a_ potential_ aerial_ biosphere_ on_ Venus_I_Cosmic_ Rays].

Achinthya Nanayakkara (30.03.2025)

Originally published - 2021 (now removed)

Originally written - 2019